63 Eu Europium

Click image to magnify. Strongly oxidized piece of europium, 1 gram. Original size in cm: 0.5 x 2
Europium is a very reactive metal, which actually has a silvery color, but oxidizes quickly in air. It is toxic and is the most ignoble of the lanthanoids after lanthanum. It has its most important application as red and blue luminescent substance, e.g in CRT television sets. The phenomenon fluorescence was named after fluorites with Eu2+ inclusores.